


Mild Stomach Poison

by ImNotAMarySue (writethatdownpls)



Category: Fire Emblem: Fuukasetsugetsu | Fire Emblem: Three Houses
Genre: Attempt at Humor, Fire Emblem: Three Houses Golden Deer Route, M/M, The whole ensemble - Freeform, do you remember that lost object which was a bottle of mild stomach posion?, except for edelgard and dimitri, i repeat this is gay, it's male byleth, this is gay, too many people honestly, we going golden deer my friends, yeah claude didn't remember it
Language: English
Status: Completed
Published: 2020-02-15
Updated: 2020-02-15
Packaged: 2021-02-27 18:40:07
Rating: Teen And Up Audiences
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 4,086
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/22740361
Author URL: https://archiveofourown.org/users/writethatdownpls/pseuds/ImNotAMarySue
Summary: "I found this five years ago in the Golden Deer classroom."“Uhm… What is that, exactly?”“Oh, judging by its components, it’s mild stomach poison,” Byleth clarified. “Likely with a laxative effect.”
Relationships: My Unit | Byleth & Claude von Riegan, My Unit | Byleth/Claude von Riegan
Comments: 4
Kudos: 99





	Mild Stomach Poison

**Author's Note:**

> You know what? I don't know what I'm doing anymore. Just take it.
> 
> (If this has been done before trust me I had NO idea, I haven't read a single Fire Emblem fic in my entire life. Which I guess it's a mistake. Should read something soon).
> 
> Important. English is not my mother language, I'm actually from Spain. But I'm studying English Philology, so trust me when I say that I've done my very best to correct this... whatever this is. This is also relevant because I play the game... in Spanish. So there might be some discrepancies with how characters talk or... idk. I really tried my best.

"Wait a second," Byleth startled everyone in the room as the noise of the chairs being moved had barely extended through the tables. 

Claude looked strangely at him. He had just said that the meeting was over, and his teacher (Byleth, he should start calling him Byleth, right? They weren't his students anymore. Goddess, it was so weird...) had seemed to agree. Or, at least, to not want do add anything else. He had almost looked impressed at the strategy Claude had suggested. The look in his eyes had almost felt like an actual pat in the back. 

Sweet, sweet approval from an authority figure. Or, well, someone Claude respected so much. Yeah. Claude respected his teacher. It was just respect. Nothing else. 

And it was their first war meeting. Just the first! Claude wasn’t about to fuck it up so soon.

"Is… is there anything else you wanted to add, teach? Is something wrong?" Claude looked at him, sitting at his right, and said those words with a slightly nervous undertone. 

It cannot be that his strategy was wrong. It was right, it had to be right, it was a good plan and he KNEW it. Hilda would mock him anyway, Lorenz would look a bit annoyed, but it was a fact that his plan was great. And— and he didn't want to disappoint Byleth so soon after his return. 

Nope, nope, nope. He had grown up, he was smarter, it had been 5 years, for Sothis’ sake. Claude couldn’t— He couldn’t—

"Not really," Byleth said. "Please, everyone, sit again," a few tired puffs came from the section where the ex-Black Eagles were sitting. Those had been Caspar and Dorothea, no doubt about that. Petra and Ferdinand were too polite to do that. 

...If Petra had understood at all what was going on. Couldn’t blame her, though. Claude already spoke the language and yet there were some times he couldn’t understand shit.

Oh, and Lindhard was actually… sleeping. Of course. 

"Then? What is it?" Claude continued asking, seeing how Mercedes shrugged her shoulders at something Felix had just whispered, apparently. 

Claude was still practicing how to read lips. Felix didn't look very happy. Although he was Felix so, who knew if he was actually mad or if it was just his usual expression. 

Claude had to work on that, too. 

"It's about this," and saying so, Byleth stood up and took something out his pocket, showing it to all his ex-pupils and then leaving it on the table in front of him. 

It took Claude a couple of seconds to Realize. 

"I found this five years ago in the Golden Deer classroom," Byleth began explaining. "If I remember correctly, every one of you was in my class already during that time, except for…" he paused for a second, "Dorothea. You only joined a couple of weeks later, so you can leave. Also, anyone who cannot be strictly considered as a student, you can go too. I’m pretty sure this is not yours.”

"Oh, hell no. I'm staying," Dorothea, known for having a sixth sense for gossip (and also for being an incredible singer, yada, yada, not the point), refused with a grin. Manuela seemed to have the same idea, but the rest of them (Cyril and Shamir leading them, they were quick to get the hell out of the room) left without commenting anything else, just looking strangely at what Byleth had just brought out.

"As you wish," Byleth nodded. 

"What is—" Seteth approached and whispered to Byleth, but the teacher was fast to shoosh him away with a hand gesture. Seteth sighed and joined Flayn and the rest and quickly left the room. 

"The thing is" Byleth started, "at the time I thought it was too risky to return this bottle to its owner, whoever it was, so I was expecting to the end of the school year to confront you all until I found out who had lost it. But Edelgard…" he didn't finish the sentence, but it didn't matter. That was the longest some people had heard him talk ever. I was quite a thing. His old students were in awe. And also, everyone understood what was left unsaid.

Claude, however, had started sweating. And Hilda was looking straight at him.

“So it has stayed with me these last five years,” Byleth concluded. Everyone waited for him to keep talking, but he didn’t.

So, eventually, someone raised her hand.

“Yes, Annette?”

“Uhm… What is that, exactly?” Annette asked from her place among the ex-Blue Lions.

“Oh, judging by its components, it’s mild stomach poison,” Byleth clarified. “Likely with a laxative effect.”

Claude sweated more profusely. He could feel Hilda’s eyes piercing his skull, but he forced himself to look at Byleth, trying to look natural.

Hah, natural.

He had almost forgotten he had lost that small bottle. Almost.

“Not mine,” announced Petra, shaking her head. She then proceeded to stand up and leave the room with decision. No one tried to stop her. It was Petra. It was a possibility she had bought it by mistake, but if she said it wasn’t hers, it just wasn’t hers. 

Also, obviously Claude knew it wasn’t hers.

“Oh. But what if someone was ill? I mean, professor, it could be medicine,” Annette said raising her hand a little bit. As if she had to keep asking for permission to talk.

“As I already said, it states that it's poison,” Byleth said plainly. “This is not intended to be medicine.”

"That… that seems logical, yes. Oh, well, it isn't mine, of course!" Annette was fast to say. "I wouldn't—" 

"No one is saying is yours, Annette," Felix sighed, interrupting her, "although I wouldn't be surprised if you bought it by mistake and then lost it."

"Felix! I wouldn't!" Annette looked outraged, although Felix wasn't necessarily putting his natural meanness into those words. 

"Buy it or lose it?" 

"Anyway," Byleth cut the conversation before poor Annette turned redder. Claude could only hope he didn't look as obviously ashamed as he felt under Hilda's eyes, "I'm not interested in why or how, I just want to return it."

There was a long silence. No one stood up. No one moved. No one said a word. Byleth looked at each and every one of them. 

Claude took that time to calm himself. Right. He couldn’t just  _ say _ it was his. Like, it was likely everyone and their mothers at least suspected he used to be the owner of that little bottle. He had that kind of reputation, and he was actually proud of it. Or, well,  _ had _ been proud of it.

But now he was the leader of the Alliance. Claude had to seem  _ respectable _ , at least. And just going back like that to what everyone knew he tried to do five years ago…

And, like. Professor Byleth couldn’t be serious, right? Well, he was pretty serious on a normal basis but— yeah. That. He could be joking. He had done that sometimes in the past while looking dead-serious.

Something Claude had always found… amusing. Yeah. Amusing.

“Does the owner want to step forward?” Byleth said after a whole minute. “No?”

“I-I mean, teach…” Claude found himself saying. “What does it matter anymore? The poison probably expired at some point during these five years, it’s not like someone might want it back when they can’t even give it use. Or its owner might not remember its theirs anymore.”

“I still want to return it,” Byleth simply said.

“ _ Why _ ?” Claude asked.

“I have to. I’m not keeping it.”

“Then why don’t just throw it away?” Lysithea intervened, looking kinda bothered by the whole scene. Some other people made noises of agreement. Felix, Leonie, Lorenz, Caspar…

Linhardt snored. Changed the position of his head. Claude wished to be able to live so relaxedly.

But the past was coming back to bite him in the ass and shit on his face. Quite literally.

“The owner might still be looking for it.”

“But no one’s stepping forward, so it’s just as Claude said. It’s been too long, even for my tastes,” Caspar said after a couple of seconds. Probably the blue-haired guy didn’t even suspect it was Claude’s, he just didn’t look like he cared about the culprit, for once. For once! That moment should be recorded in history books. “So what’s the point?”

Good! Even Caspar was on his side. Even if he didn’t know it was Claude’s side, specifically.

“Also, I have to go to the bathroom,” Caspar added. “Can we finish this quickly?”

...Or it might be just that he wanted to leave to go to the bathroom and was just throwing excuses to leave fast.

“The point is that I want to return it,” Byleth repeated quite calmly. “And you’ll be able to go to the bathroom once we’ve finished.”

_ ‘Oh my goddess, he’s a stubborn dumbass,’  _ Claude thought, blushing hard. He blushed because he was ashamed. Yeah. Definitely ashamed. 

As Claude DEFINITELY blushed (and covered his face to hide it, pretending tiredness) there was a general exasperated sigh.

“Professor, no offense, but we’re adults. Can’t we just… let the matter go?” Ingrid asked.

“I want to return it,” Byleth said once again.

“Okay, okay, then it’s mine,” to Claude’s surprise, Hilda finally tore her eyes away from him and looked at Byleth, her right hand up like she was signaling her defeat.

What the f—

“No, it’s not yours. You can leave, Hilda,” Byleth said.

There was another silence. Hilda’s mouth gaped, astonished. Seeing on Byleth’s face that he was dead serious, she stood up and left the room. And immediately the whole bunch of the original Golden Deers looked straight at him. 

Lorenz's look was specially unbearable. He had gotten better at making Claude feel ashamed with the years. And okay, in a normal situation Claude could totally deal with it and even counter the purple haired guy, but that wasn't a normal situation. 

As Hilda closed the door, Claude could feel his hopes and dreams escaping away with her. 

_ 'Bye, bitch,'  _ they said. 

  
Claude was the bitch.

“Professor… excuse me but what the hell? She just said it was hers,” Sylvain said.

“But it wasn’t hers.”

“How do you know?”

“I just do.”

Sylvain opened his mouth and closed it a few times. It was kinda amusing watching how Sylvain was left without words for once, but… 

This was really exasperating for everyone present except for Manuela and Dorothea, who seemed to be having the time of their lives, actually. Dorothea had silently sat in the chair previously occupied by Catherine and had started to comment on the scene in whispers with Manuela, who sat just at her right. 

How did they manage to contain their laughs? That was a mystery for another day.

“Then what if I confess it’s mine? Can I leave?” Sylvain asked finally. 

“Actually, yes. You can leave.”

And just like that, Sylvain left, not without sticking out his tongue to everyone present before closing the door.

He hadn’t even confessed. He had just asked about confessing.

Dorothea finally laughed out loud after that. No one bothered to look at her. 

“Professor, are you sure it’s not his?” Ingrid asked, brow furrowing. “I mean, we’re talking about Sylvain here.”

“I don’t think it’s his, no,” Byleth confirmed.

“But do you know who is the owner? If you know then why the hell are we doing this?” Felix sounded as tired as he looked.

But Byleth didn’t answer. He limited himself to look at the ones who were still present.

“Then it was me! Can I go now?” Claude said in a joking tone.

“No, you can’t,” Byleth answered looking directly at him. 

Hey—

“Wait— why?” 

“Because you’re our leader. You have to supervise the situation.”

Claude left his mouth hanging open. 

"I don't think… this is a situation that requires my supervision," be fumbled with his words. This… this was… 

"It actually does require it. Please bear with me here until we've found the owner," Byleth said. 

Great, Claude was stuck there. Just so… great. And the serious look Byleth was giving him left no place for protesting. 

Also, that look was hot. Oh, did Claude really just thought that? 

Fuck him. It was no time to think that… stuff.

_ 'Hey, Claude, what the fuck?'  _

"Oh, I already said it wasn't me before, can I go?" Annette asked then. 

"Yes," Byleth responded curtly. 

_ 'I'm going to combust here,'  _ Claude thought just as Annette left the room as fast as she could. Sylvain's chatting could be heard the seconds the thick wooden door was open, and then it disappeared again. 

"Also," Byleth started as the door closed, "the original Golden Deer class except for Claude can also leave. I know you too well to know none of you would buy or use something like this."

"Heck, YES!" Lysithea jumped out of her seat, startling Marianne. 

Linhardt also seemed startled, as he raised his head and opened his eyes. But then dropped it again between his arms.

"Darling, your mouth!" Lorenz reprimanded her, but the young woman was already making her way out of the room. 

"What's this about?" Claude heard how Raphael asked. 

"No idea but let's just go," Ignatz answered him. 

They all left in quick succession, Marianne giving the still trapped people a small bow with her head. 

And the door was closed again.

"This is Claudephobia," Claude mumbled, crossing his arms. 

"Yes, it is," Byleth answered, his eyes still going over everyone present. 

Okay, fair. 

A sleeping Linhardt, a gaping Caspar, a confused Ferdinand, an about to cry Bernadetta, an annoyed Felix, an outraged Ingrid, an astonished Ashe, a seemingly uninterested Mercedes, and a couple of gossipers called Manuela and Dorothea were still in the room. And of course, Claude and Byleth were still there. 

Great, just great. 

“Bernadetta, you can go,” Byleth said after a minute. “And take Linhardt with you, if you don’t mind.”

“ _ Why? _ ” Claude whispered to the air as the girl let out a wail of relief. 

“Because we’re talking about Bernadetta and Linhardt,” again, Byleth answered when Claude wasn’t expecting it.

And, okay, he was  _ right _ .

“Do you really see me capable of owning such a thing?” Ferdinand asked as Bernadetta struggled to wake up Linhardt.

“Not really. Please help Bernadetta and go,” Byleth accepted.

Amazing. Just amazing. 

"Now, who's the owner?" Dorothea intervened for the first time as the last Black Eagles except from Caspar left the room. Claude was honestly surprised, he was just starting to think the singer wouldn't say anything to anyone except from Manuela… And that she had opened her mouth kinda worried him. "C'mon, guys, just say it already. Although I can't believe you would buy such things, every day that passes I'm more surprised with how nobles behave." 

“Well, technically…” Ashe started, but Mercedes placed a hand on his shoulder.

"Don't look at me, I have nothing to do with this!" Caspar complained. "You lost me when Sylvain went, I have NO idea of who would the owner be."

"Is that your testimony?" 

"My  _ what _ ?" Caspar blinked. 

"I'll take it as an affirmation," with a sigh, Dorothea stood up. "Can I, professor?" 

"The floor is yours, Dorothea," Byleth confirmed. 

_ Oh, no.  _

"So!" She started, a smile on her face that gave Claude goosebumps. "Caspar pleads innocent," she got to the center of the room after circling the section of tables. She turned around towards the Blue Lions, "what about you?" 

Claude could just watch the scene. He had already said it was his (half-joking, right, but he had done it), and Byleth had immediately turned him down. What was he supposed to do? And what the hell was Byleth doing, exactly? Claude had stopped understanding his actions a long time ago, but this was on another level. 

"Not mine," said Felix. 

"I don't think it's mine, no," Ashe commented. 

"Hmmm… I think I would recall if I had bought something like that," Mercedes seemed as calm as ever, her words soft. 

"Definitely not mine," finished Ingrid. 

"I believe the four of you. You can grab your things and go," said Byleth immediately, Dorothea made a small reverence towards the door, indicating them the exit.

"Finally," Felix groaned. 

"Is this a joke?" Caspar asked quietly as the Blue Lions quickly stood up and turned to leave. "Is this a joke?!" Caspar repeated louder. 

_ 'Same,'  _ Claude thought. Was Caspar really going to take responsibility for his actions? Just like that? 

No. Okay, no, he couldn't just stand there and let Caspar take the blame. Claude wasn't like that. 

"Okay, Byleth," Claude sighed, standing up. The door closed, "that's it, this is entirely my fault, that—" 

"Claude, sit down," Byleth cut him again. Manuela looked attentively at the scene, Dorothea sat on top of one of the tables and Caspar seemed close to a breakdown. 

"This is bullshit! It's not mine!" 

"I know."

"I don't know what made you believe it's mine but that isn't true!" 

"I know it isn't yours," Byleth continued calmly. 

"And I have to say that— wait, what?" 

"I know it isn't yours," Byleth repeated. 

Caspar was left speechless. Just like Claude. Manuela looked quite confused and Dorothea was just smiling. 

"You can go, Caspar," Byleth went on. 

"Can… I?" 

"Yes, you can." 

"Is not a trap?" 

"No, it isn't."

"Oh. Okay. Okay," still not trusting entirely Byleth's words, and pure confusion reflected on his face, Caspar grabbed his stuff and was fast to abandon the room. 

There was a silence. 

"Hey, Claude," without more delay, Byleth took the little bottle and forced Claude to grab it.

"Oh my goddess, this was surprisingly fun!" Dorothea laughed. "Can we do this again sometime?" 

"No, Dorothea."

"Wait, wha—" 

"What's going on here? Is Claude the owner? Did you know?" Manuela interrupted before Claude could actually ask. 

"Oh, right. Sorry, professor Manuela, we didn't told you," Byleth bowed a little his head. 

"To be fair we weren't expecting you to stay," Dorothea added. "We'll fill you in next time, promise."

"There's not going to be a next time," Byleth started. Then turned towards Manuela. "I've been knowing the owner was Claude since the moment I picked it up five years ago," he declared. "It's obvious. Sorry, Claude,” he didn’t even look at the leader of the Alliance. “And also, it actually has his name written on the bottom."

Oh.

Oh, yeah, there it was. Claude had actually done that. Written that. Fuck himself. 

"Please just… just explain yourselves already," Claude said veeery slowly, although he didn’t know if he wanted to hear it.

He didn’t want to because he was gonna die out of shame, probably, but he needed to know.

"Professor Byleth wanted to test you," it was Dorothea who answered, "know how would you react given the situation in which your friends and allies would be blamed or tried to take the blame for something you were responsible for."

"I already knew how you would've reacted 5 years ago. And the conclusion is that now you have behaved just as you would have behaved then. When you saw I was going to let Caspar take your blame, you stepped in,” completed Byleth, finally looking at Claude.

"After all, the rest weren't under any 'threat' at any point," Dorothea pointed out. "Professor let them leave as soon as they said it wasn't their fault, and even invited them to go if they were getting nervous. He even said he just wanted to return the poison. Nothing more. Now, where you going to recognize out loud that it was yours when the moment of truth arrived?"

That was a rhetorical question, right? It had to be.

"I should have let Bernadetta go first, though, but I somehow got distracted…" Byleth trailed off, ignoring Dorothea's last words. 

"It's okay, professor. I'll go check on her later."

"Good," Byleth nodded. 

"And you didn't fill me in?" Manuela asked again, pouting and all. Melodramatic as she could only be. 

"Next time, professor, next time."

"Again, there won't be a next time," Byleth clarified. "Dorothea was just notified in order to intervene in case things got out of hand. Thankfully that hasn't happened. You last intervention was actually unnecessary."

"I'm a good actress AND I wanted to have some fun, too," she shrugged. As if she hadn’t been laughing and enjoying the scene the entire time. "And also it was convenient I was the last to join the Golden Deer."

"Quite convenient, yes."

Claude saw and listened them talk like it was a theater play. He was just there, a probably expired bottle of mild stomach poison in his right hand, mouth slightly agape. He felt as he was getting smaller and smaller, and his face grew hotter and hotter.

He was going to combust, yep.

All of that had been… astonishingly clever. He had just been thinking Byleth was dumb two minutes before AND he had found him hot because of that. 

Yes, he actually recognized he, Claude von Riegan, had found his former professor, Byleth Eisner, hot.

...Anyway.

Claude looked straight (or not so straight, given the circumstances) at his former teacher. 

The events that had just transpired had just been on another level. Byleth wasn’t dumb. Hadn’t been dumb that time, at least. He had been very clever.

That. That was quite hot indeed.

"I'm sorry I had to do it like this, but I found it was necessary to test you, Claude," Byleth said. "Keep being like this and bettering yourself and you're really going to be a great leader."

Oh.

Oh, fuck.

Claude was actually gonna daydream with those words AND that look AND that voice AND those li—

"Oh, but please throw away that bottle. It has actually been with me for five years and it's better not to test if it keeps working or not," he added. 

"OR if it's effects have been increased! Oh, testing that would be interesting..." 

"Dorothea, please," Manuela gave her a bad look, but Dorothea just laughed. Again. 

“Just joking,” she said. With a little jump she stood again on her feet. “C’mon, professor Manuela, let’s leave professor Byleth and Claude alone.”

“Okay— Why?” Manuela asked as she was standing up.

“Oh…” Dorothea looked pensive for a second, “they should have a lot to talk about.”

Claude furrowed his brow. Talk about what? Was Byleth going to reprimand him in the end? He wasn’t a teenager anymore. And he had done the right thing in the end. The reunion had also finished, though, and Byleth had seemed quite alright with everything that had been said. What could possibly—

Oh, and there they went Dorothea and Manuela.

…

OH, NO, THAT MEANT HE WAS GOING TO BE ALONE WITH BYLETH?

“Ahahaha, well, I better get going now!” Claude said, trying to pretend he was okay and miserably failing. That voice had came out an octave higher.

“Wait,” faster than Claude could process, Byleth reached out and grabbed his shoulder, standing in front of him.

…

Uhm…

“Uhm…” Claude said, 10 seconds later, still in the same position. He was actually frozen in place. Quite ironic, because he felt like he was on fire, specially in the area Byleth was touching. “Teach? I have stuff to do.”

“Do you?” Byleth asked.

And no, not really. Like, yeah, he probably had stuff to do, and if he didn’t someone would totally give him work to do. Disadvantages of being a leader, apparently, who would have thought?

But he couldn’t stay there. Nope. 

“Y-yes,” Claude tried to sound confident and, again, failed.

He had just admitted to himself he was whipped for Byleth like, 30 seconds ago, could life give him a break?

“Okay, if you say so, then…” Byleth leaned forward and whispered to his ear: “I’ll see you around, Claude.”

And actually Claude ended up being the only person left in the room, as Byleth turned around and left without saying anything else.

What the hell. What the actual hell. Blessed Sothis, if she even existed, Claude had to take a second. Or two. Or one hour. What the hell.

He dropped down into his chair once again, staring off into the space, still trying to catch his breath. 

Maybe if he hadn’t been so… affected, by Byleth’s presence, he would have noticed the very unusual smile on his teacher’s lips.

Oh, well. Byleth was gonna have a lot of opportunities to tease the young leader.

**Author's Note:**

> Can you believe this is my second FE3H oneshot? I don't actually believe it. I haven't written oneshots in my entire life. Not until now.
> 
> Wow, I'm deep into this hell. Anyway.
> 
> Thanks chisi (@chisiuwu on twitter) for partially reading this before publishing it. You're a kind soul. And you, reader, take a look at her account. She draws fire emblem and oh, god, she's GOOD. GOOD!!! VERY GOOD!!!
> 
> Feel free to leave kudos or comments if you're feeling generous. You can also get mad at me at my twitter (same handle as here, ImNotAMarySue) for writing this amount of bullshit and make you read it. I will 100% understand it.


End file.
